ULP System Power Supply - ULP System Guide IEC

Power Supply Distribution Systems

The power supply distribution system can be installed following either of these topologies:

Star topology:

In a cubicle, the star supply distribution system is recommended to minimize EMC disturbances due to common impedance.
Daisy chain topology:

The daisy chain supply distribution system enables service continuity: a device can be disconnected without impacting the others and the common impedance and voltage drop on devices are limited.

Star Supply Distribution System

The following diagram shows the design of a star supply distribution system (DC or AC). In this configuration, only the link between the main power supply and the terminal distribution is common impedance. The common impedance is minimized. The shorter the cable length (C), the lower the common impedance.

The wiring of each device must be done with twisted-pair cables to avoid loops and radiated emissions.

A	Power supply
B	0 V connection of power supply
C	Cable between power supply and terminal distribution
D	Terminal distribution
E	Device (D1–Dn)

Daisy Chain Supply Distribution System

The devices in the system are connected in a daisy chain and a loop, in which the first and the last device are connected directly to the power supply.

The cables between the daisy chain and the loop for reconnecting to the power supply must be close together to avoid current loop and generation of EMC disturbances.

The following diagram shows the design of a daisy chain supply distribution system in a single cubicle. In this configuration, additional wiring closing the daisy chain is required.

A	Power supply
B	0 V connection of power supply
C	Device (D1–Dn)
D	D Last device connected to the power supply on the line

Wiring closing the daisy chain

Power Supply Distribution in a System with Several Cubicles

In a power supply distribution system with several cubicles, it is possible to feed three or four devices per line if the current consumption is low (less than 500 mA) and the total length is less than 5 m (16.4 ft).

The following diagram shows the design of the power supply distribution system in a global system with several cubicles:

The devices (D1–Dn) are connected in a star to reduce common impedance.
The cubicles (C1–Cn) are connected in a daisy chain with additional loop wiring to minimize drop voltage, reduce common impedance, and provide service continuity.

	Cubicles connected in daisy chain topology with cables for reconnecting to the power supply close to the loop
	Devices connected in star topology

ULP Module Consumption

To limit voltage drops on the ULP cords, the consumption of each RJ45 ULP port is limited to 300 mA.

The following table lists ULP module consumption.

Module	Typical consumption (24 Vdc at 20 °C / 68 °F)	Maximum consumption (19.2 Vdc at 60 °C / 140 °F)
IFE Ethernet interface for one circuit breaker	100 mA	140 mA
IFE Ethernet switchboard server	100 mA	140 mA
EIFE embedded Ethernet interface for one MasterPact MTZ drawout circuit breaker	115 mA	180 mA
IFM Modbus-SL interface for one circuit breaker	21 mA	30 mA
IO input/output application module for one circuit breaker	100 mA	130 mA
FDM121 front display module for one circuit breaker	21 mA	30 mA
MicroLogic 5, 6, or 7 trip unit for ComPacT NSX circuit breakers	30 mA	55 mA
MicroLogic X control unit for MasterPact MTZ circuit breaker (powered through ULP port module)	200 mA	335 mA
BSCM circuit breaker status control module for ComPacT NSX circuit breaker	9 mA	15 mA
MicroLogic trip units for MasterPact NT/NW and ComPacT NS circuit breakers	100 mA	100 mA
BCM ULP circuit breaker communication module for MasterPact NT/NW and ComPacT NS circuit breakers	40 mA	65 mA
Service Interface	0 mA (the Service Interface has its own power supply)	0 mA (the Service Interface has its own power supply)
USB maintenance interface	0 mA (the USB maintenance interface has its own power supply)	0 mA (the USB maintenance interface has its own power supply)

Power Supply Characteristics

NOTICE
LOSS OF DOUBLE INSULATION Supply the MicroLogic X control unit with a 24 Vdc Safety Extra Low Voltage (SELV) power supply only, connected through the ULP port module or through the terminal block for external power supply (F1- F2+). Pay attention to the polarity. Do not connect devices which do not have double insulation to the 24 Vdc SELV power supply which is being used to supply the MicroLogic X control unit. For example, do not use the same 24 Vdc SELV power supply to supply a MicroLogic X control unit for MasterPact MTZ circuit breakers and a MicroLogic A/E/P/H trip unit for MasterPact NT/NW circuit breakers. Failure to follow these instructions will result in a basic/single insulated system.

NOTICE

LOSS OF DOUBLE INSULATION

Supply the MicroLogic X control unit with a 24 Vdc Safety Extra Low Voltage (SELV) power supply only, connected through the ULP port module or through the terminal block for external power supply (F1- F2+). Pay attention to the polarity.
Do not connect devices which do not have double insulation to the 24 Vdc SELV power supply which is being used to supply the MicroLogic X control unit. For example, do not use the same 24 Vdc SELV power supply to supply a MicroLogic X control unit for MasterPact MTZ circuit breakers and a MicroLogic A/E/P/H trip unit for MasterPact NT/NW circuit breakers.

Failure to follow these instructions will result in a basic/single insulated system.

The 24 Vdc power supplies of the ULP system must be SELV to provide insulation coordination (IEC 60664-1 and IEC 61204-7) and distribute a SELV along the entire length of the ULP connections. The 24 Vdc power supply must be connected at the primary end to a low-voltage distribution zone, whose overvoltage category is less than or the same as that of the 24 Vdc power supply:

Power supplies in overvoltage category IV can be connected directly to the busbar system of a main low voltage distribution board.

Schneider Electric AD power supplies are overvoltage category IV.
Power supplies in an overvoltage category lower than IV cannot be connected directly to the busbar system of a main low voltage distribution board. A minimum of one circuit isolation transformer is therefore needed between the busbar system of a main low voltage distribution board and a control circuit that can be connected to the primary of the 24 Vdc power supply.

Schneider Electric Phaseo ABL8 power supplies are overvoltage category II, like most standard power supplies.

The 24 Vdc SELV power supplies of the ULP system can be used to power other devices on condition that they have double insulation or reinforced insulation to retain the SELV nature of the power supply. These devices must not connect either the 0 V or the 24 Vdc to the local machine ground or the protective ground.

0 V Connection

0 V of power supply can be connected to local ground or be floating. The following table presents the use cases and their recommendations.

0 V connection	Requirements	Recommendations
0 V connected to ground	TN-S earthing system Meshed earth The devices are powered with the same power supply. The power supply is installed in the same electrical equipment as the devices. One or more connections of 0 V to ground: 0 V of devices is not connected to ground in the installation comprising the power supply and the devices.	Check that the common mode voltage between phase and ground is not higher than 7 Vac. Otherwise, add one power supply to reduce the load.
Floating 0 V	If one or more of the requirements to connect 0 V to ground is not met, the 0 V of the power supply must be kept floating.	It is recommended to use an insulation monitoring device (Vigilohm IM20, for example) to detect the first phase-to-ground fault and improve continuity of service.

Power Supply Rating

Power supply rating rules are as follows:

To design the power supply dedicated to communication modules, check the maximum short-circuit current (Icc). It must not exceed 20 A. This is the maximum short-circuit current which can be withstood by the ULP modules. For example, the Icc of the ABL8 power supply is limited to 14 A for a 10 A nominal current.
The rating of the 24 Vdc power supply voltage for the furthest ULP module must be 24 Vdc +/-10% (21.6–26.4 Vdc).

To comply with this rating range at the end of a Modbus cable distributing power, the 24 Vdc power supply output voltage must be regulated at the following value:
- +/-3% (23.3–24.7 Vdc) for ABL8 power supplies.
- +/-5% (22.8–25.2 Vdc) for AD power supplies.

Recommended 24 Vdc Power Supplies

The recommended 24 Vdc power supplies are:

Schneider Electric Phaseo ABL8 power supplies (3 to 10 A, overvoltage category II), recommended for large installations.
Schneider Electric AD power supplies (1 A, overvoltage category IV), recommended in the following cases:
- For installation limited to a few IMUs.
- As power supply of MicroLogic trip units in MasterPact NT/NW or ComPacT NS circuit breakers.

Characteristic	Phaseo ABL8 Power supply	AD Power supply
Illustration
Overvoltage category	Category II per IEC 60947-1	Category IV per IEC 62477-1 (Vac model) Category III per IEC 62477-1 (Vdc model) Category III per UL 61010-1
Input supply voltage AC	110–120 Vac 200–500 Vac	110–130 Vac 200–240 Vac
Input supply voltage DC	–	24–30 Vdc 48–60 Vdc 100–125 Vdc
Dielectric withstand strength	Input/output: 4 kV RMS for 1 minute Input/ground: 3 kV RMS for 1 minute Output/ground: 0.5 kV RMS for 1 minute	Input/output: 3 kV RMS for 1 minute (110–130 Vac and 200–240 Vac model) 3 kV RMS for 1 minute (110–125 Vdc model) 2 kV RMS for 1 minute (24–30 Vdc and 48–60 Vdc model) Input/ground: 3 kV RMS for 1 minute Output/ground: 1.5 kV RMS for 1 minute
Temperature	50 °C (122 °F) 60 °C (140 °F) with 80% nominal load maximum	70 °C (158 °F)
Output Current	Limited to 10 A	1 A
Ripple	200 mV peak-peak	200 mV peak-peak
Output voltage setting for line loss compensation	24–28.8 Vdc	22.8–25.2 Vdc

NOTE: Install a control/isolation transformer for applications requiring an overvoltage current category III, and a surge arrester for overvoltage current category IV.

Power Supply Part Numbers

Power supply	Rating	Input-Output voltage	Part number
Schneider Electric AD power supply Primary overvoltage category IV Temperature: -25 °C to +70 °C (-13 ºF to +158 °F)	1 A	24/30 Vdc - 24 Vdc	LV454440
		48/60 Vdc - 24 Vdc	LV454441
		100/125 Vdc - 24 Vdc	LV454442
		110/130 Vac - 24 Vdc	LV454443
		200/240 Vac - 24 Vdc	LV454444
Schneider Electric Phaseo ABL8 power supply Primary overvoltage category II Temperature: 0–60 °C (0–140 °F) (derated to 80% of the current above 50 °C (122 ºF))	3 A	100/500 Vac - 24 Vdc	ABL8RPS24030
	5 A	100/500 Vac - 24 Vdc	ABL8RPS24050
	10 A	100/500 Vac - 24 Vdc	ABL8RPS24100

NOTE: Example of other compliant power supplies: Phoenix Contact TRIO POWER power supply unit, TRIO-PS-2G/1AC/24DC/10/B+D (part number 2903145).

24 Vdc Power Supply Connections Rules

To reduce electromagnetic interference, follow these rules:

The input and output wires of the 24 Vdc power supply must be physically separated as much as possible.
The output wires of the 24 Vdc power supply must be twisted together.
The output wires of the 24 Vdc power supply, communication cables, or line protected by a surge protection device (SPD) must cross over the power cables perpendicularly.
The 24 Vdc power supply cables must be cut to length and be against the metallic frame of the earthed enclosure. Do not loop excess cable.
Always flatten 24 Vdc power supply cables on the earthed metallic frame of cubicles to avoid ground loops.
To route sensitive cable, follow corners inside enclosures, taking into account the cable bending radius.

24 Vdc Power Supply Cable Characteristics

The rules for a standard installation of the 24 Vdc power supply in the ULP system are as follows:

Connect the power supply to a cable with one twisted pair.
The minimum distance between power supply cable and other signals in the installation must be as follows:
- Distance between power and control circuits = 100 mm (3.9 in)
- Distance between power circuit and 24 Vdc or communication cables = 200 mm (7.9 in)
- Distance between control circuit and 24 Vdc or communication cables = 100 mm (3.9 in)

To limit electromagnetic interference, apply the following additional installation rules:

Connect the power supply to a one twisted-pair shielded cable.
The cable shield must be connected to EMC clamps.
The brass clamps must have suitable diameter for the cable type and fixings compatible with the installation, for example, screw or DIN rail (for example, EMClip^® SKHZ brass clamps from Indu-Sol).

24 Vdc Power Supply Load Balance

The power supply rating depends on the load balance, determined by the consumption of the devices in the IMU. Follow this procedure to verify that the power supply rating is correct:

Step	Action
1	Calculate the load balance of the power supply taking into account the ULP module consumption. Refer to ULP Module Consumption.
2	Measure the voltage on the last device connected to the power supply on the line.
3	Check that the measurement is compatible with the device tolerance.
4	In case of voltage drop, do one of the following: Increase the cross-section of the power supply cable. Make a loop to the power supply from the last cubicle in a daisy-chain architecture or the last device in the electrical equipment.

24 Vdc Power Supply Mode

NOTICE
HAZARD OF EQUIPMENT DAMAGE Use the same 24 Vdc SELV AD or Phaseo ABL8 power supply to supply power to all ULP modules of one IMU. Failure to follow these instructions can result in equipment damage.

The same 24 Vdc SELV power supply can be used to supply several IMUs, depending on the overall power requirements of the system.
Use a separate 24 Vdc power supply to supply the MN/MX/XF voltage releases or the MCH gear motor.

Module	Power supply mode
IFE Ethernet interface for one circuit breaker	Must be connected to a 24 Vdc power supply and cannot be powered through its ULP port.
IFE Ethernet switchboard server	Must be connected to a 24 Vdc power supply and cannot be powered through its ULP port.
IFM Modbus-SL interface for one circuit breaker	Must be connected to a 24 Vdc power supply⁽¹⁾ and cannot be powered through its ULP port.
IO input/output application module for one circuit breaker	Must be connected to a 24 Vdc power supply and cannot be powered through its ULP port.
ULP port module for MasterPact MTZ circuit breakers	Must be connected to a 24 Vdc power supply and cannot be powered through its ULP port.
MicroLogic X control unit for MasterPact MTZ circuit breakers	Powered by the ULP port module.
EIFE embedded Ethernet interface for one MasterPact MTZ drawout circuit breaker	Powered by the ULP port module.
FDM121 front display module for one circuit breaker	Must be connected to a power supply if alone or not located at the end of the ULP line. Powered by the other ULP modules through the ULP cord if located at the end of the ULP line.
MicroLogic 5, 6, or 7 trip unit for ComPacT NSX circuit breakers	Powered by the other ULP modules through the ULP cord.
BSCM circuit breaker status control module for ComPacT NSX circuit breakers	Powered by the other ULP modules through the ULP cord.
MicroLogic trip unit for MasterPact NT/NW and ComPacT NS circuit breakers	Must be powered by a dedicated AD power supply.
BCM ULP circuit breaker communication module for MasterPact NT/NW and ComPacT NS circuit breakers	Powered by the other ULP modules through the ULP cord.
(1) The connection of an IFM interface to the 24 Vdc power supply depends on the IFM assembly: If the IFM interface is stacked to an IFE server, only the IFE server must be powered by a 24 Vdc power supply. If the IFM interfaces are stacked without IFE server, only one of the IFM interfaces must be powered by a 24 Vdc power supply. A single IFM interface must be powered by a 24 Vdc power supply.

24 Vdc Power Supply for MicroLogic Trip Units in MasterPact NT/NW and ComPacT NS Circuit Breakers

NOTICE
HAZARD OF NUISANCE TRIPPING IN NOISY ENVIRONMENT Use a separate 24 Vdc AD power supply to supply the MicroLogic trip unit in MasterPact NT/NW or ComPacT NS circuit breakers and its optional M2C or M6C programmable contacts. Failure to follow these instructions can result in nuisance tripping

One 24 Vdc SELV AD power supply can supply power to several MicroLogic trip units in MasterPact NT/NW or ComPacT NS circuit breakers, depending on the overall power requirements of the system:

Up to ten MicroLogic trip units without M2C or M6C programmable contacts.
Up to five MicroLogic trip units with M2C or M6C programmable contacts.